Parkes observations for project P1295 semester 2023OCTS_03

We propose observing time with the Parkes telescope to investigate four ``spider" millisecond pulsars (MSPs), PSR J1048+2339 (a redback spider), PSR J1908+2105 (an MSP that occupies a region of parameter space between black widows and redbacks), PSR J2052+1219 and PSR J2256-1024 (black widow spiders). Spider MSPs are commonly seen to exhibit frequency-dependent eclipsing. Observations with wide bandwidth telescopes like Parkes UWL (700-4000 MHz) will be extremely useful to study the eclipse mechanisms in these systems. Eclipse properties of spider MSPs are hitherto unexplored at the frequency regime available with the Parkes UWL receiver. We propose to investigate a sample of 4 MSPs mentioned above (for which polarization has not been studied) with the Parkes telescope using the UWL receiver in full polar mode, which will be addressed with this proposal. One of the aims is to model the eclipse phase spectra using wideband observations of these pulsars in an optically thick-to-thin transitioning regime (optical depth nearly 1), to explore the eclipse mechanism.\n Observing the possible changes in rotation measure (RM) at eclipse ingress and egress will allow us to probe the magnetic field in the eclipse boundaries. \n We request to cover nearly one full orbit for each of these MSPs. Thus we propose 23 hours of observing time including time for setup and calibration in each epoch with the Parkes UWL receiver for the investigation of the eclipse mechanism as well as the polarization, profile evolution, and spectra of four spider MSPs.

本研究提议申请帕克斯望远镜（Parkes Telescope）的观测时长，对4颗“蜘蛛类”毫秒脉冲星（millisecond pulsars, MSPs）开展研究：PSR J1048+2339（红背蜘蛛型毫秒脉冲星）、PSR J1908+2105（处于黑寡妇与红背蜘蛛类脉冲星参数空间交界区域的毫秒脉冲星）、PSR J2052+1219以及PSR J2256-1024（黑寡妇型毫秒脉冲星）。蜘蛛类毫秒脉冲星普遍表现出与频率相关的食掩现象。借助帕克斯UWL接收机（700-4000 MHz）这类宽频带望远镜开展观测，将对研究此类系统的食掩机制极具价值。目前针对蜘蛛类毫秒脉冲星的食掩特性，在帕克斯UWL接收机覆盖的频率范围内尚未有相关探索。本研究提议利用帕克斯望远镜的UWL接收机全偏振模式，对上述4颗此前尚未开展偏振研究的毫秒脉冲星样本展开研究，此为本提案的核心研究方向之一。本研究的目标之一是，通过对处于光厚至光薄过渡状态（光深（optical depth）近似为1）的这些脉冲星开展宽频带观测，构建食掩相位光谱模型，以此探究食掩机制。观测食掩进入和退出阶段的旋转测量（rotation measure, RM）变化，将有助于我们探测食掩边界处的磁场。我们计划为每颗毫秒脉冲星覆盖近乎完整的轨道周期。因此，本提案提议使用帕克斯UWL接收机，为每个观测历元申请总计23小时的观测时长（含设备架设与校准时间），以开展上述4颗蜘蛛类毫秒脉冲星的食掩机制、偏振特性、轮廓演化及光谱研究。